Well the car was running very well based on how it used to run - only real problem was it had an oil leak that hits the headers and smokes. But I took the car out today after adding an air dam since I had none and I wanted to see how it did on the highway. I had the car out on the city streets earlier with the new air dam for ~30 minutes, and the fans never needed to come on because the temp never even passed the 220 mark. So I took it out and a few things happened:

1. Brakes became very hard after driving for say, 5 minutes.
2. Coolant temp gauge went wacky and bounced around between 220 and 160 - by wacky I mean like it was boucning around as if it were following music, lol. Then it passed 220 on the highway?, so fans went on and could only keep the car at 220.
3. Voltage gauge never even hit 13 volts; and here's another problem I've been having - the car will sometimes start immediately, but other times it takes a TON of cranking for oil pressure to build past 30 and then it'll start. It did this today, only wouldn't start; I jumped it and it started immediately. (Bad battery maybe?).

Only thing cooling related that was done was my heater core blew up the other day so I temporarily bypassed it by connecting the inlet/outlet hoses.

I'm basically looking for things to consider as faulty for this to happen. Thanks in advance for any help.

 

I would check your coolant level. Sometimes with low coolant the sensor is not submerged in coolant and therefore, gives erroneous temp readings.

With the engine off, key off, measure the battery voltage. It should read about 12.5V.

 

Thanks for the reply; yeah, one of the first things I checked was the coolant level, it was normal. And the battery has always been around 12.3-12.7V with everything off, same today. It normally passes 13V on the gauge when running, but this time it didn't. I'm debating getting a new battery, but this one is only just over a year old. THe fact that the last time I had the car out (about a week and a half ago) everything was great. All of this happened this time and the only change was removing the heater core.

 

There's no reason your coolant temp gauge should be bouncing around like that unless it's faulty.

Your problem is not related to the fans if you are overheating on the highway, the airspeed should be enough to cool the radiator down.

You either have too low of a coolant level.

Faulty thermostat that could be sticking.

Or the air dam could be installed wrong.

To test your thermostat remove it from the housing, clean it off, then suspend it in a small container and fill it with 195 degree water (or whatever temperature your thermostat is rated to) and see whether it opens up. Give a couple of degrees either way before you buy a new one. They're only like 10 dollars so it's no big deal.

As for the voltage issue, do you mean it never hit 13 volts while the car was running? That's bad, probably is your alternator but you should get that checked out, autozone checks batterys, starters, and alternators for free.

What do you mean brakes became very hard driving? The pedal became stiff? Or they became difficult to actuate?

If it's the former then it could be your brake booster, you can test it by sitting in the car with it off, pressing the pedal and then starting the car, your foot should sink a couple of inches.

If it's the latter then you have low brake pressure, check your fluid level.


Hope this helps, keep us updated.

 

Ok, well the air dam I would assume is installed correctly, because it didn't even come close to overheating when driving for about 30 minutes in the city, and before the air dam, it would hit 220 after merely 5 minutes of driving. It's installed in the factory location using the factory mounting holes, so I don't think my problem lies there.

Coolant level is good.

Thermostat is a few months old, but I can check on it to make sure it's working, but again, the fact that it stayed below 220 for so long with no fan assistance I would think it's functioning properly.

Gauge could be faulty, but it only did it for a short while, then was fine the rest of the ride (unless is was just steadily reading wrong, which is possible).

As for voltage, I mean it never even reached the 13V mark on the gauge while running - and it normally surpasses it (~14V?).

By hard, I mean the pedal became VERY stiff - There was almost no pedal travel. The brakes worked ok, but the pedal was extremely hard.

I'll check on the booster test and let you know.

What puzzles me is that this all happened at the same time...these cars are fun, lol.

 

Alright, went out and checked the booster. Looks good; applied the brake with the car off and when I started it, the pedal dropped a couple of inches. Any other tests for a bad booster? Fluid level is also good.

Forgot to mention in the last post, the alternator is also under 1 year old with maybe 100 miles on it...would hope it's not shot.

 

Hm, that's strange that it all occurred at the same time.

I'm not sure about another way to test the booster, I'll look it up in my haynes manual, lemmie get back to you on that.

I'm stumped on the overheating issue though, it just doesn't make sense that your car could be overheating at highway speeds with a functioning thermostat/water pump/pressurized system.

Make sure you aren't losing coolant out of that jury-rigged heater core bypass.

I know thermostats have bypasses that allow them to still flow if there's a malfunction with the device so still check up on that.

As for the battery, you should have the alternator checked, the alternator powers the car while it's on so it has to be a problem with that. Pull it and take it to autozone and have them check it for you, like I said, it's free so it'll just be a bit of work to remove the belt and unbolt the alternator. Might as well though, you shouldn't be getting such a low voltage reading.

Does the voltage fluctuate if you rev the engine? Could be a bad voltage regulator if so.

Get back to us.

 

Have you tested the check valve on the brakes vacuum hose? Remove and check: you should be able to suck air through it, but not blow through it.

Make sure nothing is blocking airflow over the radiator.

If you want to test the gauge, locate the sender in the head (single green wire). With the key on, unplug it and it should read full cold. Ground the green wire and it should peg full hot.

 

Alright guys, thanks. I'll see if I can't get the alternator out and tested tomorrow. The two lines that ran into the heater core are still intact, simply connected with an elbow - and the rubber was still in great shape and there are no leaks at the connection - one of the first things I checked too thinking I had a bad connection. The voltage doesn't vary at all with RPM, just constantly lower than it should be.

I replaced the check valve when I redid a large portion of the car's vacuum lines, so it's new, but I'll still check to make sure it's functional. Nothing is blocking flow to the radiator, but I'll also default check the sender and report back with findings tomorrow.



**About the booster test - I checked my Haynes and shop manual and all I got was the same test you suggested earlier, hold with engine off...turn on engine...pedal should fall. Mine does just that.

 

Thanks for the help guys. Took the alternator to Autozone - passed all tests three times, so that's good. Check valve wouldn't work at all - air wouldn't go in or out, so it's been replaced. The coolant temp sender tested ok as well - cold unplugged, hot grounded.

Anything else to look at?

 

Hm, that's a stumper, what else could it possibly be causing it to heat up? You checked the radiator cap too? Make sure the thermostat is opening.

I don't think it could be the water pump, because this problem doesn't occur all the time correct? If it is a constant problem of the heat being high then perhaps the vanes on the pump could be wearing.

And I'm stumped on the alternator, you should be getting a good 15 volts at least with the car running.

 

Yeah, the cooling issue is really bugging me too, especially since I'm moving to Colorado soon and this car may turn into a daily driver for awhile until I acquire my next car. The radiator cap is brand new, the old one wasn't holding pressure. I'll check on the thermostat's functioning tomorrow. I don't believe the problem is constant, but it only happened this time and I haven't driven it since. I did check the voltage with the car off and running today - off = 12.7, running = 14.5. And that was steady. Should it be over 15 or is 14.5 normal on a stock charging system (105A alt.)?

Wanted to add, when I changed out the brake booster check valve, the pedal went from almost immediately firm when applied, to very long pedal travel before the brakes "bite". What I mean is before, I had the car set up so that the brake pedal produced friction at the pads with only a small amount of pedal travel, and today, when I changed out the valve, the pedal now drops significantly before delivering the same results. Ideas?

 

Yes, definitely test your thermostat, I don't really think it could be that because the problem is so intermittent, but might as well.

12.7 is a perfect voltage reading off of the battery while the car is not running. I have a sheet that says where it should be while running, it's between 14 and 15 I believe.

You should be able to pump the brakes and that should decrease the pedal travel each time because you are building pressure in the brake system, if that doesn't work then you either have air in the system and you need to bleed it or you have a shortage of fluid.

 

Yeah, I know that it sounds as though air is in the brake lines, but I literally just changed the check valve out - it was normal yesterday, and with a new check valve it's like this. The fluid level is perfect in the reservoir. I can't see how changing the vacuum check valve let air into the lines? Unless the faulty valve made the brakes feel fine, and this working one reveals the true state of the brakes? IDK, this whole situation is messed up, lol.

 

Hm, I don't see how it could have let air in the system by changing the check valve.

Well I guess if you think about it from that perspective it could have possibly made it more difficult to feel air in the system because of such a stiff brake pedal. And now that you have a properly functioning booster the air in the system can be "felt" more.

 

Thermostat's good - opened right at 180*.

 

whats about air pockets ? since you did mess with the hoses you could have a pocket of air in the system and wont come out . acts just like a car that has the purge valves in the coolant system and wasnt purged right.temp guadge would spike up and down but that would only concern the coolant issues. it could also throw other things things off , chk your oil presser with a gauge at the filter then up top by the intake and compare pressure it can help trouble shoot internal issues flex the hoses and see if you can purge the air out some see if it helps.

 

altenator when you get it chked is it cold or hot , you could have a resistor pack in the alt regular going out causing issues , if it is cold it could have a connection and heat soaked it could give you issues , cold metal contracts, hot metal expands, i have seen many times were you would get issues when the engine heats up and the regulator in the altator freaks out

 

Well on the coolant system, the highest spot is the radiator cap (at least I can't see anything higher) so wouldn't the air make it's way up there, and when I opened the cap to inspect the fluid wouldn't it have escaped? I can try flexing some of the hoses to work possible air pockets out.

The alternator was cold when tested. Apart from running the car for awhile and then getting the alternator tested (my engine compartment gets pretty warm, and might pose problems when removing the alternator) is there any way to test it when it's warm, i.e. things to look for while it's still installed?

 

only way is a clamp on meter for amp and volt meter for voltage while your cars running, other way is like pepboys or someplace that can test it while its running

 

Ok, got the car tested while the alternator was hot and it was good. So is it possible the hard starting is a crappy battery? It's not that old, but the fact that when I had jumper cables on it, it started immediately once the key hit 'RUN', as opposed to cranking forever, makes me think the battery must be junk. Any thoughts? This is one thing I need to have working right - I want it to start the first time every time; and not have to be jumped every time I want to start the car, lol.

 

i had a 89 rs that would heatup just like yours everything looked great.. until i checked infront of the rad i had all kinds of crap in that little space leaves cigg packs a dead bird and lots of other stuff . I pulled the rad out cleaned all that garbage out of there and no more issues

 

I know the radiator is clog free - it's new along with the motor (< 200 miles). There is nothing blocking flow to the front of the radiator either, I checked that when I was putting the air dam on. What bugs me is that it ran so cool in the city less than a week prior, and then went funny.

 

Just had another thought regarding the heater core bypass. The connection doesn't appear to be leaking, but to eliminate the possibility that the connection is a problem, could I simply not allow coolant to pass through it? What I'm getting at is that I read on the forums that having your temp control set to COLD basically cuts off coolant flow to the heater core. Is this true? If it is, and I keep the setting to COLD, and the problem persists, then I know it lies elsewhere. Thoughts?

 

hey i just got a 1986 camaro with a 92 v8 5.7 liter engine in it . the car was running really crappy so i had to change firing order on the car it was running alot better.. but still wasnt right about a week later i discovred the smog silinoid was disconnected from the terminal where it goes into the top of the engine also the electric was not pluged into the conponent. i did some research and found out the correct way to hook it up .. i started and drove the car about 5 blocks car seamed to be running better then ever smooth and more power . after i turned the car off and tryed to start it up the next day .. car does not start .. as u hold the exnition and pump the gas the engine gets slowly to full running speed as if its running and when i let go of the exnition it turnes off as quick as i let go ?? i also tryed removing the smog silinoid back to how i org found it still same story any suggestions ?? thanks

 

hey i just got a 1986 camaro with a 92 v8 5.7 liter engine in it . the car was running really crappy so i had to change firing order on the car it was running alot better.. but still wasnt right about a week later i discovred the smog silinoid was disconnected from the terminal where it goes into the top of the engine also the electric was not pluged into the conponent. i did some research and found out the correct way to hook it up .. i started and drove the car about 5 blocks car seamed to be running better then ever smooth and more power . after i turned the car off and tryed to start it up the next day .. car does not start .. as u hold the exnition and pump the gas the engine gets slowly to full running speed as if its running and when i let go of the exnition it turnes off as quick as i let go ?? i also tryed removing the smog silinoid back to how i org found it still same story any suggestions ?? thanks

 

Anyone have any input as to whether setting your temp control to COLD bypasses the heater core hose routing?